Transition metal complexes comprising one noncarbene ligand and one or two carbene ligands and their use in OLEDs

1. A heteroleptic carbene complex of the general formula (I)

M 1 [carbene] n [het]m   (I)

comprising both carbene ligands and heterocyclic noncarbene ligands,

in which the symbols are each defined as follows:

M 1 is a metal atom selected from the group consisting of Ir(III), Os(II), or Rh(III);

n is the number of carbene ligands, where n is 2, where the carbene ligands may be the same or different;

m is the number of heterocyclic noncarbene ligands, where is 1;

where

carbene is a carbene ligand of the general formula (II)

where the symbols in the carbine ligand of the general formula II are each defined as follows:

Do 1 is N

r is 1;

p is 0;

q is 0;

Y 1 and Y 2 together form a bridge between the donor atom Do l and the nitrogen atom N, said bridge having two carbon atoms,

R 1 and R 2 together form a bridge having a total of from four carbon atoms, so that the group

 forms a six-membered ring which, in addition to the double bond already present has two further double bonds, and may optionally be substituted by alkyl or aryl groups and/or groups with donor or acceptor action;

Y 3 is hydrogen, an alkyl, alkynyl or alkenyl radical, or

where Do 2 , q′, s′ R 3 ′, R 1 ′, R 2 ′, X′ and p′ are each independently as defined for Do 2 , q, s, R 3 , R 1 , R 2 , X and p,

and

het is a heterocyclic noncarbene ligand of the general formula (III)

in which the symbols in the ligand het of the general formula III are each defined as follows:

D are each independently CR 34 or N;

W is C, N, or P;

E are each independently CR 35 , N, NR 36 , S, O, P or PR 37 ;

I is 1 or 2;

R 34 , R 35 , R 37 are each independently H, an alkyl, aryl, heteroaryl, alkynyl or alkenyl radical, R 36 is H, an alkyl, heteroaryl, alkynyl, or alkenyl radical or an aryl radical with a base structure selected from phenyl, naphthyl, anthracenyl and phenanthrenyl which base structure is unsubstituted, or in each case 2 R 34 , R 35 , R 36 or R 37 radicals together form a fused ring which may optionally comprise at least one heteroatom, or R 34 , R 35 , R 36 or R 37 is a radical having donor or acceptor action;

where the dotted line means an optional bridge between one of the D groups and one of the E groups; where the bridge may be defined as follows:

alkylene, arylene, heteroarylene, alkynylene, alkenylene, NR 38 , PR 39 , BR 40 , O, S, SO, SO 2 , SiR 41 R 42 , CO, CO—O, O—CO and (CR 43 R 44 ) v, where one or more nonadjacent (CR 43 R 44 ) groups may be replaced by NR 38 , PR 39 , BR 40 , O, S, SO, SO 2 , SiR 41 R 42 , CO, CO—O, or O—CO, where

v is from 2 to 10;

and

R 38 , R 39 , R 40 , R 41 , R 42 R43 R 44 are each H, alkyl, aryl, heteroaryl, alkenyl, or alkynyl.

2. The carbene complex according to claim 1 , wherein the moiety

is selected from the group consisting of

in which the symbols are each defined as follows:

Z″ are each independently CR 10 or N;

R 4 , R 5 , R 6 , R 7 , R 8 , and R9 are each hydrogen, alkyl, aryl, heteroaryl, alkynyl or alkenyl or a substituent with donor or acceptor action;

R 10 is hydrogen, alkyl, aryl, heteroaryl, alkynyl or alkenyl, or in each case 2 R 10 radicals together form a fused ring which may optionally comprise at least one heteroatom, or R 10 is a radical with donor or acceptor action;

in addition, R 4 or R 5 in the moiety a, R 8 in the moiety b, one of the R 10 radicals in the moiety c and R 11 in the moiety d may be bonded to R 1 via a bridge, where the bridge may be defined as follows:

alkylene, arylene, heteroarylene, alkynylene, alkenylene, NR 18 , PR 19 ,BR 20 , O, S, SO, SO 2 , SiR 30 R 31 , CO, CO—O, O—CO and (CR 21 R 22 ) x , where one or more nonadjacent (CR 21 R 22 ) groups may be replaced by NR 18 , PR 19 , BR 20 , O, S, SO, SO 2 , SiR 30 R 31 , CO, CO—O, or O—CO, where

x is from 2 to 10; and

R 18 , R 19 , R 20 , R 21 , R 22 , R 30 R 31 are each H, alkyl, aryl, heteroaryl, alkenyl, or alkynyl.

3. The carbene complex according to claim 1 , wherein the moiety

has the structure

in which the symbols are each defined as follows:

Z are each independently CR 12 ;

R 12 in the Z groups are each independently H, an alkyl, aryl, heteroaryl, alkynyl, or alkenyl radical, or in each case 2 R 12 radicals together form a fused ring which may optionally comprise at least one heteroatom, or R 12 is a radical with donor or acceptor action.

4. The carbene complex according to claim 1 , wherein the at least one carbene ligand is selected from the group consisting of

where the symbols are each defined as follows:

Y 3 is an alkyl, alkynyl or alkenyl radical

or

a group of the following structure

Z is the same or different and is CR 12 ;

Z′ is the same or different and is CR 12 ′ or N;

Z″ is the same or different and is CR 10 or N;

R 12 , R 12 ′ are the same or different and are each independently H, an alkyl, aryl, heteroaryl, alkynyl or alkenyl radical, or in each case 2 R 12 or R 12 ′ radicals together form a fused ring which may optionally comprise at least one heteroatom, or R 12 or R 12′ is a radical with donor or acceptor action;

R 4 , R 5 , R 6 , R 7 ,R 8 and R 9 are each hydrogen alkyl , aryl , heteroaryl, alkynyl or alkenyl, or a radical with donor or acceptor action;

R 10 in the Z″ groups are each independently H, alkyl, aryl, heteroaryl, alkynyl or alkenyl, or in each case 2 R 10 radicals together form a fused ring which may optionally comprise at least one heteroatom, or R 10 is a radical with donor or acceptor action.

5. The carbene complex according to claim 1 , wherein the heterocyclic noncarbene ligand het is selected from the group consisting of

where

D are each independently CR 34 or N;

R 34 and R 35 , are each independently H, an alkyl, aryl, heteroaryl, alkynyl or alkenyl radical, R 36 is H, an alkyl, heteroaryl, alkynyl, or alkenyl radical or an aryl radical with a base structure selected from phenyl, naphthyl, anthracenyl and phenanthrenyl which base structure is unsubstituted, or in each case 2 R 34 , R 35 or R 36 radicals together form a fused ring which may optionally comprise at least one heteroatom, or R 34 , R 35 or R 36 is a radical with donor or acceptor action.

6. The carbene complex according to claim 1 , wherein M1 is Ir(III) and n =2 and m =1.

7. The carbene complex according to claim 6 , wherein the carbene complex has the general formula (Ii):

where the symbols in the carbene complexes of the general formula (Ii) are each defined as follows:

Do 1 is N;

r is 1;

p is 0;

q is 0;

Y 1 and Y 2 together form a bridge between the donor atom Do l and the nitrogen atom N which has two carbon atoms,

R 1 and R 2 together form a bridge having a total of from four carbon atoms, so that the group

 forms a six-membered ring which in addition to the double bond already present has two further double bonds, and may optionally be substituted by alkyl or aryl groups and/or groups with donor or acceptor action;

Y 3 is hydrogen, an alkyl, alkynyl or alkenyl radical,

or

 where Do 2 ′, q′, s′, R 3 ′, R 1 ′, R 2 ′, X′ and p′ are each independently as defined for Do 2 , q, s, R 3 , R′, R 2 , X and p;

D are each independently CR 34 or N;

W is C, N, or P;

E are each independently CR 35 , N, NR 36 , S, O, P or PR 37 ;

I is 1 or 2;

R 34 , R 35 , R 37 are each independently H, an alkyl, aryl, heteroaryl, alkynyl or alkenyl radical, R 36 is H, an alkyl, heteroaryl, alkynyl, or alkenyl radical or an aryl radical with a base structure selected from phenyl, naphthyl, anthracenyl and phenanthrenyl which base structure is unsubstituted, or in each case 2 R 34 , R 35 , R 36 or R 37 radicals together form a fused ring which may optionally comprise at least one heteroatom, or R 34 , R 35 , R 36 or R 37 is a radical with donor or acceptor action;

where the radicals, groups and indices R 1 , R 2 , R 3 , Do 1 , Do 2 , Y 1 , Y 2 , Y 3 , X, p. q and r in the carbene ligands in the compounds of the general formula li may each be the same or different;

where the dotted line means an optional bridge between one of the D groups and one of the E groups; where the bridge may be defined as follows:

alkylene, arylene, heteroarylene, alkynylene, alkenylene, NR 38 , PR 39 , BR 40 , O, S, SO, SO 2 , SiR 41 R 42 , CO, CO—O, O—CO and (CR 43 R 44 )where one or more nonadjacent (CR 43 R 44 ) groups may be replaced by NR 38 , PR 39 , BR 40 , O, S, SO, SO 2 , SiR 41 R 42 , CO, CO—O, or O—CO, where

v is from 2 to 10;

and

R 38 , R 39 , R 40 , R 41 , R 42 , R 43 , R 44 are H, alkyl, aryl, heteroaryl, alkenyl, or alkynyl.

8. A process for preparing heteroleptic carbene complexes of the general formula I according to claim 1 , wherein the preparation comprises the following step:

reaction of at least one ligand precursor of the general formula (IV)

in which

Q − is a monoanionic counterion, preferably halide;

and

G is H;

and

the further symbols in the ligand precursor of the general formula IV are each defined as follows:

Do 1 is N;

r is 1;

p is 0;

q is 0;

Y 1 and Y 2 together form a bridge between the donor atom Do l and the nitrogen atom N, said bridge having two carbon atoms

R 1 and R 2 together form a bridge having a total of from four carbon atoms, so that the group

 forms a six-membered ring which, in addition to the double bond already present has two further double bonds, and may optionally be substituted by alkyl or aryl groups and/or groups with donor or acceptor action;

Y 3 is hydrogen, an alkyl, alkynyl or alkenyl radical, or

where Do 2 ′, q′, s′, R 3 ′, R 1 ′, R 2 ′, X′ and p′ are each independently as defined for Do 2 , q, s, R 3 , R 1 , R 2 , X and p;

and

at least one ligand precursor of the general formula V

in which:

D are each independently CR 34 or N;

W is C, N, or P;

E are each independently CR 35 , N, NR 36 , S, O, P or PR 37 ;

I is 1 or 2;

R 34 , R 35 , R 37 are each independently H, an alkyl, aryl, heteroaryl, alkynyl or alkenyl radical, R 36 is H, an alkyl, heteroaryl, alkynyl, or alkenyl radical or an aryl radical with a base structure selected from phenyl, naphthyl, anthracenyl and phenanthrenyl which base structure is unsubstituted, or in each case 2 R 34 , R 35 , R 36 or R 37 radicals together form a fused ring which may optionally comprise at least one heteroatom, or R 34 , R 35 , R 36 or R 37 is a radical with donor or acceptor action;

with a metal complex comprising at least one metal M 1 ′, where M 1 ′ is defined as follows:

M 1 ′ is a metal atom selected from the group consisting of Ir(III), Os(II), and Rh(III).

9. The process according to claim 8 , wherein the metal M 1 used is Ir(III)

10. An organic light-emitting diode comprising at least one heteroleptic carbene complex according to claim 1 .

11. A light-emitting layer comprising at least one heteroleptic carbene complex according to claim 1 .

12. An organic light-emitting diode comprising at least one light-emitting layer according to claim 11 .

13. A device selected from the group consisting of stationary visual display units mobile visual display units, comprising at least one organic light-emitting diode according to claim 10 .

14. A device selected from the group consisting of stationary visual display units and mobile visual display units comprising at least one organic light-emitting diode according to claim 12 .